Heat dissipation device

ABSTRACT

A heat dissipation device includes a chamber, a tube, a wick structure and a plurality of fins arranged around the tube. The chamber includes a base and a cover hermetically connected to the base. An evaporation room is defined between the base and the cover of the chamber. The tube extends upwardly from the cover of the chamber, and defines a condensation room communicating with the evaporation room. The wick structure is immerged with working fluid, and includes a main portion disposed in the evaporation room and a projection extending from the main portion into the condensation room.

BACKGROUND

1. Technical Field

The disclosure generally relates to heat dissipation devices, and more particularly to a heat dissipation device having a low heat resistance.

2. Description of Related Art

With continuing development of the electronic technology, electronic components such as CPUs are generating more and more heat which is required to be dissipated immediately. A heat dissipation device is usually adopted for cooling the electronic component.

Generally, a heat dissipation device includes a heat spreader, a fin unit and a heat pipe. The heat spreader attaches to an electronic component to absorb heat therefrom. The heat pipe has an evaporation end attaching to the heat spreader and a condensing end attaching to the fin unit to transfer heat of the electronic component to the fin unit for dissipation. However, a heat resistance existed between the heat spreader and the evaporation end of the heat pipe limits a heat transfer efficiency between the heat spreader and the heat pipe, and thus a heat dissipation efficiency of the heat dissipation device is limited even through the heat pipe transferring heat through phase change has a much better heat transfer efficiency.

For the foregoing reasons, therefore, there is a need in the art for a heat dissipation device which overcomes the limitations described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric, assembled view of a heat dissipation device according to an exemplary embodiment.

FIG. 2 is an exploded view of the heat dissipation device of FIG. 1.

FIG. 3 is an exploded view of a heat transfer member of the heat dissipation device of FIG. 2.

FIG. 4 is a cross section of the heat dissipation device, taken along line IV-IV of FIG. 1.

FIG. 5 is a cross section of the heat dissipation device, taken along line V-V of FIG. 1.

DETAILED DESCRIPTION

Referring to FIG. 1, a heat dissipation device for cooling heat generating components (not shown), such as electronic components, according to an exemplary embodiment includes a heat transfer member 10 and a heat dissipation member 20 connected to the heat transfer member 10.

As shown in FIGS. 2 and 3, the heat transfer member 10 is hollow. A wick structure 18 immerged with working fluid, such as alcohol, water, etc., is received in the heat transfer member 10. The heat transfer member 10 includes a chamber 14 and two tubes 16 extending upwardly from the chamber 14. The tubes 16 are spaced from each other, and both are perpendicular to the chamber 14.

Referring to FIG. 4, the chamber 14 includes a base 144 and a cover 142 coupled to the base 144 firmly and hermetically. The base 144 and the cover 142 each have a rectangular main plate 143 and a flange 145 extending from an outer periphery of the main plate 143. The flanges 145 of the cover 142 and the base 144 are connected together to form an evaporation room 147 between the cover 142 and the base 144. Four arms 146 extend outwardly from four corners of the base 144, respectively. Each arm 146 defines a through hole 149 therein for a screw extending therethrough to assemble the heat dissipation device to the heat generating component.

A pair of apertures 30 are defined in a middle of the main plate 143 of the cover 142 of the chamber 14, and spaced from each other. Each of the apertures 30 has nearly an elongated rectangular shape with two arc ends. A wall 15 extends upwardly from a border of each aperture 30. The walls 15 are aslant to the lateral sides of the cover 142, and are aslant to each other. Each wall 15 slants from a lower left towards an upper right. A distance between the walls 15 gradually decreases from the lower left to the upper right. The walls 15 have shapes and sizes substantially identical to each other. Each wall 15 includes a pair of linear sides 141 parallel to each other, and two arced sides 140 at opposite ends of the linear sides 141. A length of the wall 15, i.e., a distance between the arced sides 140 of the wall 15, is much larger than a width of the wall 15 i.e., a distance between the linear sides 141 of the wall 15.

The tubes 16 are substantially identical to each other, and are respectively connected to the walls 15 of the cover 142. Each tube 16 includes a pair of flat plates 162, a pair of arced plates 164, and a top plate 166. The flat plates 162 and the arced plates 164 each extend vertically. The flat plates 162 are parallel to each other, the arced plates 164 are connected at lateral sides of the flat plate 162. The top plate 166 couples top sides of the flat plates 162 and the arced plates 164. Thus a condensation room 168 is defined in each tube 16 among the flat plates 162, the arced plates 164 and the top plate 166 with a top end being closed by the top plate 166. Bottom end of each tube 16 is inserted into a corresponding wall 15 of the cover 142 of the chamber 14, and connected to the corresponding wall 15 closely. Thus the condensation room 168 of each tube 16 communicates the evaporation room 147 of the chamber 14 through the corresponding aperture 30.

The wick structure 18 is a screen mesh, and defines a plurality of micro-pores therein. Alternatively, the wick structure 18 can be other type, such as sintered power. The wick structure 18 includes a main portion 181 and a pair of projections 182. Both of the main portion 181 and the projections 182 are flat. The main portion 181 is arranged in the evaporation room 147 of the chamber 14 and attaches the base 144 of the chamber 14 closely. A thickness of the main portion 181 of the wick structure 18 is smaller than a height of the evaporation chamber 14, and thus the main portion 181 of the wick structure 18 is spaced from the cover 142 of the chamber 14.

The projections 182 extend perpendicularly from the main portion 181 into the condensation rooms 168 of the tubes 16, respectively. Each projection 182 of the wick structure 18 has a height a little smaller than that of the tube 16. A length of each projection 182 is smaller than that of the tube 16, i.e., a distance between the arced plates 164 of each tube 16. A thickness of each projection 182 substantially equals to a width of the tube 16, i.e., a distance between the flat plates 162 of the tube 16. As shown in FIGS. 4 and 5, each projection 182 of the wick structure 18 in a corresponding tube 16 abuts the flat plates 162 of the tube 16, and spaces from the arced plates 164 and the closed plate of the tube 16. A channel 40 is thus defined in each tube 16 between the wick structure 18 and the arced plates 164 of the tube 16 for vapor flowing upwardly to transfer heat to the heat dissipation member 20.

The heat dissipation member 20 includes a plurality of stacked fins 21 parallel to each other. Each fin 21 has a main body 22 and four hems 24 bent from four corners of the main body 22, respectively. Distal edges of the hems 24 of each fin 21 contact with the main body 22 of an adjacent fin 21 to form an air passage 23 between neighboring fins 21. A pair of openings 222 are defined in each fin 21 for receiving the tubes 16. The shape, size and location of the openings 222 are decided according to the tubes 16. A protrusion 224 extends upwardly from a border of each opening 222 of each fin 21 with a height nearly equaling to the distance between two adjacent fins 21. When the fins 21 are assembled together, the protrusion 224 of each fin 21 contacts the border of the opening 222 of the adjacent fin 21. Thus, the openings 222 cooperatively form a pair of columned holes for the tubes 16 extending therethrough, respectively, and the protrusions 224 enclose and contact with the tubes 16, which enlarges the contacting surface area between the tubes 16 and the fins 21.

During operation, the main plate 143 of the base 144 of the chamber 14 of the heat transfer member 10 attaches to the heat generating component tightly to absorb heat thereform. The working fluid that is contained in the chamber 14 absorbs heat and evaporates substantially and moves to the tubes 16 along the channels 40. Evaporated working fluid is cooled at the tubes 16 and condensed, whereby the heat is thus released to the fins 21. Finally, the condensed working fluid flows back quickly to the chamber 14 on the action of the wick structure 18 to begin another cycle of heat dissipation. Since the heat transfer member 10 has the chamber 14 and the tubes 16, the chamber 14 can absorb heat directly and thus a heat resistance between a heat spreader and a heat pipe of a conventional heat dissipation device is avoided; therefore, the heat of the heat generating component can be transferred to the heat dissipation member 20 almost immediately. A heat dissipation efficiency of the heat dissipation device is thus enhanced.

It is to be understood, however, that even though numerous characteristics and advantages of the disclosure have been set forth in the foregoing description, together with details of the structure and function of the disclosure, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A heat dissipation device, comprising: a heat transfer member comprising a hollow chamber and at least a hollow tube extending from and communicating the chamber, the at least one tube being substantially perpendicular to the chamber; a wick structure immerged with working fluid comprising a first section received in the chamber and at least one second section extending from the first section into the at least one tube, a channel being defined between the at least one tube and the wick structure for vapor flowing in the at least one tube; and a heat dissipation member comprising a plurality of fins arranged around the at least one tube.
 2. The heat dissipation device of claim 1, wherein the chamber is flat, the at least one tube extending upwardly from a middle of the chamber, a cross section of the at least one tube having a substantially elongated rectangular shape with two arc ends.
 3. The heat dissipation device of claim 2, wherein the at least one tube comprises two flat plates, two arced plates respectively formed at lateral sides of the flat plates, and a top plate coupling to top sides of the flat plates and the arced plates, the at least one second section of the wick structure abutting the flat plates and spaced from the arced plates of the at least one tube, the channel being defined between the arced plates of the at least one tube and the at least one second section of the wick structure.
 4. The heat dissipation device of claim 3, wherein the at least one second section of the wick structure is spaced from the top plate of the at least one tube.
 5. The heat dissipation device of claim 1, wherein the chamber comprises a base and a cover parallel to and spaced from the base, the first section of the wick structure attaching to the base and spaced from the cover.
 6. The heat dissipation device of claim 5, wherein at least one aperture is defined in the cover and has a substantially elongated rectangular shape with two arc ends, a wall extending upwardly from a border of the at least one aperture, the at least one tube having a bottom end inserted into and connected to the wall hermetically.
 7. The heat dissipation device of claim 5, wherein a plurality of arms extend outwards from the base and each define a through hole for assembly the heat dissipation device.
 8. The heat dissipation device of claim 1, wherein the at least one tube comprises a pair of tubes, the pair of tubes are aslant to each other.
 9. A heat dissipation device, comprising: a chamber comprising a base and a cover hermetically connected to the base, an evaporation room being defined between the base and the cover of the chamber; a tube extending upwardly from the cover of the chamber, and defining a condensation room therein communicating the evaporation room of the chamber; a wick structure immerged with working fluid comprising a main portion disposed in the evaporation room and a projection extending from the main portion into the condensation room; and a plurality of fins arranged around the tube.
 10. The heat dissipation device of claim 9, wherein the tube is flat, comprising two flat plates, two arced plates respectively connecting lateral sides of the flat plates, and a top plate coupling to top sides of the flat plates and the arced plates, the projection of the wick structure abutting the flat plates and spaced from the arced plates, a channel being defined between the arced plates of the tube and the projection of the wick structure.
 11. The heat dissipation device of claim 10, wherein a top end of the projection is lower than the top plate of the tube.
 12. The heat dissipation device of claim 9, wherein the wick structure is a screen mesh.
 13. The heat dissipation device of claim 9, wherein an aperture is defined in the cover and has a substantially elongated rectangular shape with two arc ends, a wall extending upwardly from a border of the aperture, a bottom end of the tube inserted into and connected to the wall hermetically.
 14. The heat dissipation device of claim 9, wherein a plurality of arms extend outwards from the base and each define a through hole. 